Contact assembly for dry cell battery

ABSTRACT

A contact assembly for connecting the terminals of a dry cell stack to the external terminals of a battery is described in which a conductive contact plate connects the top terminal of the cell stack to a first battery terminal. A connector strip nonconductively attached to the contact plate connects the bottom terminal of the stack with a second battery terminal. A method for assembling the connector assembly is also described.

United States Patent Hamel Feb. 6, 1973 CONTACT ASSEMBLY FOR DRY CELLBATTERY 3,440,105 4/1969 Yamamoto et a1. 136/108 Primary ExaminerDonaldL. Walton Att0rneyRobert H. Robinson, Raymond L. Balfour, Anthony J.Rossi and Thomas A. Lennox [57] ABSTRACT A contact assembly forconnecting the terminals of a dry cell stack to the external terminalsof a battery is described in which a conductive contact plate connectsthe top terminal of the cell stack to a first battery terminal. Aconnector strip nonconductively attached to the contact plate connectsthe bottom terminal of the stack with a second battery terminal. Amethod for assembling the connector assembly is also described.

7 Claims, 4 Drawing Figures PATENTEU E 6 3 3, 7 15, 240

v/r/ I 1158a Fig I INVENTOR.

DAVID o. HAMEL CONTACT ASSEMBLY FOR DRY CELL BATTERY CROSS REFERENCES TORELATED APPLICATIONS Co-pending application U.S. Ser. No. 46,429, filedJune 15, l970 since issued as US. Pat. No. 3,655,456 on Apr. 11,1970.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to multicell primary dry batteries. In particular, it relates tothe means of making electrical connections in such batteries.

2. Description of the Prior Art The advent of small transistorizedradios has produced a market for miniature 9 volt dry cell batteries.These batteries often comprise a pack of six layer type cells enclosedin a metal housing and having two snap type terminals located at one endof the battery. The need for these batteries is increasing andmanufacturers are searching for ways to improve these batteries andreduce their'manufacturing costs.

In a typical battery, the six cells each having a nominal terminalvoltage of 1.5 volts are placed one on top of the next and connected inseries. This gives a total voltage of 9 volts between the two ends ofthe cell pack. It has been found convenient in the design of theappliances for which these batteries are designed to have the twoterminal connections close together. To accommodate this, it has beenfound desirable to locate both terminals on a single end of the battery.This in turn requires that there be some form of wiring harness withinthe battery container'connecting the two terminals at opposite ends ofthe cell pack to the two battery terminals at one end of the battery.Many means have been tried for making the two electrical connections.One obvious means is to solder wires from battery to terminals. This wasfine for initial production but requires excessive labor when parts arebeing made in lots of thousands per day. Various forms of pressurecontacts have been used. For the most part, the pressure contacts haveprovided good electrical connections. However, it has been found thatadditional parts including necessary spacers and insulators are requiredwith the pressure contacts. These loose parts have increased thecomplexity of the battery assembly operation. As a solution to this, ithas been found expedient to make a sub-assembly in which conductormembers and insulation are fastened together by suitable attachmentmeans to form a unitized pressure contact connector.

SUMMARY OF THE INVENTION This invention describes an improved contactstrip assembly for dry cell batteries in which a metallic member servesthe multiple purposes of mounting board and first end cell to firstterminal connector. A second metallic member attached to butelectrically insulated from the first metallic member serves as thesecond end cell to second terminal connector. A principal feature of theconnector is that it can be easily assembled on a simple continuousautomatic assembly machine. The operational sequence of such a machineis also described.

The design of this invention offers several advantages over otherdesigns. It is composed of a minimum number of parts and it requires aminimum quantity of material. When assembled in accordance with thefurther teaching of this invention, the several parts of the strip arefirmly fastened together to form a single unit suitable for easyhandling in battery assembly machinery.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts an elevation of thecontact strip of the invention;

FIG. 2 shows a plan view of the same;

F IG. 3 illustrates a partial cross section view of a typical six cell,9 volt battery employing the contact strip of the invention; and

FIG. 4 indicates the several operations involved in the automaticassembly of the contact strip.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIGS. 1 and 2, a contactstrip assembly 10 is shown comprising a plate of electrically conductivematerial 12 such as conductive plastic or steel and having a rectangularshape with the corners rounded off. To this, an insulating coating 14 isadhesively attached so as to cover about one-half of the top of thecontact plate 12. The insulating coating 14 can be an adhesive paint orvarnish applied by brushing, rolling or spraying or it can be a sheet ofinsulating material such as tape. In the case of the sheet material, itis advantageous to have it coated on both sides with an adhesive.

The insulating coating 14 is brought down over the edge 16 of thecontact plate 12 so as to insulate its edge. The insulating coating canbe extended so as to cover a portion of the underside of the plate 12 asshown, or in the case of a sheet material it can be left loose. A ribbonof electrically conducting material such as steel forming a connectorstrip 20 is attached to the upper side of the insulating sheet 14 andwithin its borders as shown by the small margin of insulating strip 22.The connector strip 20 is bent at right angles around the end 16 ofplate 12. It is seen that the insulating coating lies between the twometallic parts 12 and 20 and electrically insulates one from the other.The connector strip 20 is lanced 24 in the vicinity of its end away fromcontact plate 12, so as to provide one or more contact points forcontact with the bottom cell of the cell stack.

A partial section of a six cell, 9 volt battery, FIG. 3, serves toindicate the location of the contact strip in a typical assembly. A cellstack 30 having a potential of 9 volts is made up of six 1% volt cellsconnected in series. The two terminals of the cell stack are at the top31 and bottom 33 of the stack respectively.

As is well understood, one of these terminals is positive and onenegative. For the purposes of this discussion, it is not necessary todesignate which is which other than that the stack has two terminals andthat these are of opposite polarity.

A terminal board 34 is located at the top of the battery. The terminals36 and 38 are fastened by through rivets 40 and 42 to the terminalboard.'A bottom board 44 is located at the bottom of the battery. Ametallic sleeve 46 having its ends 48 and 50 flanged over the terminalboard 34 and bottom board 44 forms the battery container and serves toclamp the assembly together. The terminal strip is located between thecell stack and terminal board. It will be seen that due to the clampingpressure supplied by flange 48, rivet 40 is in firm contact with the topof the contact plate 12 while the bottom of 12 is in firm contact withthe top terminal 31 of the cell stack. Also, due to the pressure exertedby flange 48, the rivet 42 of contact 38 is in firm contact with theconductor strip 20. The long end of the conductor strip passes down theend of the cell stack and is bent around its bottom so that the contactpoints 24 touch and make contact with the bottom contact 33 of the cellstack. Pressure from the bottom board 44 keeps the contact points 24 incontact with terminal 33. An insulating strip 52 separates and insulates the conductor strip from the metallic sleeve 46.

It will be understood from the above that the battery described is acollection of loose parts that are combined together in a single finalassembly operation. Therefore, the use of a sub-assembly such as thecontact strip of the invention, will simplify the assembly operation andreduce the chance of mispositioned parts and consequent battery rejects.v

The contact strip of this invention can be assembled using standardtools such as die sets and strip feeding devices attached to or mountedon a common mechanical punch press in ways well known in the metalworking art. An example of a suitable assembly method is shown in FIG.4. An electrically conductive ribbon 60 from which the contact platewill be cut is shown feeding in from the right hand edge of the' sketch.

A tape of insulating material 62 having an adhesive coating on bothsides and having a protective strip 64 on the top is fed to the steelstrip. The insulating tape is located so as to cover approximatelyone-half of the steel ribbon and overlap it at the front edge. At 66 theoverlapping edge of the strip 62 is shown being folded around the edgeof strip 60. At 64 the protective ribbon 64 is removed from theinsulating strip 62.

A second conductive ribbon 68 is fed at right angles to the ribbon 60.At 70 the end of the second ribbon is adhered to the top of theinsulating strip 62 by the adhesive on the top thereof. At 72 theconductive ribbon 68 is lanced to make the needed bottom contact pointsand at 74 the ribbon is cut off. At 76 a right angle bend is formed inthe second conductive ribbon and at 78 the contact plate is blanked fromthe first conductive ribbon so as to produce the finished contact strip10.

Having thus fully described the contact strip of the invention as wellas its use in the construction of a dry cell battery and a means forautomatically assembling the strip,

1 claim:

1. A dry cell battery contact assembly comprising:

a. an electrically conductive contact plate having an upper and a lowersurface;

b. an electrically insulating coating overlying and adhered to at leasta portion of the upper surface of the contact plate; and

c. an electrically conductive connector strip having a first portionoverlying and attached to a portion of the insulating coating andinsulated from the con- 6 tact plate thereby, the connector strip havinga second portion substantially perpendicular to the whereby when thecontact assembly is placed on the top of a cell pack having a lower andan upper terminal, a terminal board having two terminals mounted thereonand passing therethrough placed above the contact assembly, the end ofthe second portion of the connector strip away from the contact platebent to touch and make electrical contact with the lower terminal of thecell pack, a bottom board placed below the bent portion of the contactstrip and'a sleeve placed around the entire assemblage and flangedagainst the top of the terminal board and the bottom of the bottomboard, the first portion of the connector strip will make electricalcontact with a first terminal on the terminal board, a portion of thelower surface of the contact plate will make electrical contact with afirst terminal on the terminal board, a portion of the lower surface ofthe contact plate will make electrical contact with the upper terminalof the cell pack and a portion of the upper surface of the contact platewill make electrical contact with a second terminal on the terminalboard.

2. A dry cell battery contact assembly as defined in claim 1 in whichthe insulating material overlying a portion of the contact plate is aninsulating plate 3. A dry cell battery contact assembly as defined inclaim 1 in which the electrically conductive contact plate and theelectrically conductive connector strip are made of metal.

4. A dry cell battery contact assembly as defined in claim 2 in which:

a. the insulating tape overlying the contact plate is fastened theretoby adhesive means anda portion of the tape covers a portion of the edgeof the contact plate;

b. the electrically conductive connector strip is fastened to the top ofthe insulating tape by adhesive means and the portion of the stripsubstantially'perpendicular to the first portion is adjacent to the edgeof the contact plate and insulated therefrom by the portion of theinsulating tape covering the portion of the edge of the contact plate.

5. In a multicell dry cell battery of the type having an internal cellstack with electrical contacts at either end and external terminals atone end only of the battery and a contact strip within the battery foreffecting electrical contact between the cell stack terminals and thebattery terminals, the improvement in the contact strip which comprises:

a. an electrically conductive contact plate having an upper and a lowersurface;

an electrically insulating sheet overlying and adhered to at least aportion of the upper surface of the contact plate; and

c. an electrically conductive connector strip having a first portionoverlying and attached to a portion of the insulating sheet andinsulated from the contact plate thereby, the connector strip having asecond portion substantially perpendicular to the first portion of thestrip and having an end away from the first portion.

6. A multicell battery as defined in claim 5 in which the electricallyconductive contact plate and the electrically conductive connector stripare made of metal.

7. A multicell battery as defined in claim 5 in which:

6 a. the insulating sheet overlying the contact plate is tiallyperpendicular to the first portion is adjacent fastened thereto yadheslvfl means and a Portion to the edge of the contact plate andinsulated of the Sheet covers a portion of the edge of the therefrom bythe portion of the insulating sheet contact plate; and,

covering the portion of the edge of the contact b. the electricallyconductive connector strip is 5 fastened to the top of the insulatingsheet by adhesive means and the portion of the strip substanplate.

1. A dry cell battery contact assembly comprising: a. an electricallyconductive contact plate having an upper and a lower surface; b. anelectrically insulating coating overlying and adhered to at least aportion of the upper surface of the contact plate; and c. anelectrically conductive connector strip having a first portion overlyingand attached to a portion of the insulating coating and insulated fromthe contact plate thereby, the connector strip having a second portionsubstantially perpendicular to the first portion of the strip and havingan end away from the first portion, whereby when the contact assembly isplaced on the top of a cell pack having a lower and an upper terminal, aterminal board having two terminals mounted thereon and passingtherethrough placed above the contact assembly, the end of the secondportion of the connector strip away from the contact plate bent to touchand make electrical contact with the lower terminal of the cell pack, abottom board placed below the bent portion of the contact strip and asleeve placed around the entire assemblage and flanged against the topof the terminal board and the bottom of the bottom board, the firstportion of the connector strip will make electrical contact with a firstterminal on the terminal board, a portion of the lower surface of thecontact plate will make electrical contact with a first terminal on theterminal board, a portion of the lower surface of the contact plate willmake electrical contact with the upper terminal of the cell pack and aportion of the upper surface of the contact plate will make electricalcontact with a second terminal on the terminal board.
 2. A dry cellbattery contact assembly as defined in claim 1 in which the insulatingmaterial overlying a portion of the contact plate is an insulatingplate.
 3. A dry cell battery contact assembly as defined in claim 1 inwhich the electrically conductive contact plate and the electricallyconductive connector strip are made of metal.
 4. A dry cell batterycontact assembly as defined in claim 2 in which: a. the insulating tapeoverlying the contact plate is fastened thereto by adhesive means and aportion of the tape covers a portion of the edge of the contact plate;b. the electrically conductive connector strip is fastened to the top ofthe insulating tape by adhesive means and the portion of the stripsubstantially perpendicular to the first portion is adjacent to the edgeof the contact plate and insulated therefrom by the portion of theinsulating tape covering the portion of the edge of the contact plate.5. In a multicell dry cell battery of the type having an internal cellstack with electrical contacts at either end and external terminals atone end only of the battery and a contact strip within the battery foreffecting electrical contact between the cell stack terminals and thebattery terminals, the improvement in the contact strip which comprises:a. an electrically conductive contact plate having an upper and a lowersurface; b. an electrically insulating sheet overlying and adhered to atleast a portion of the upper surface of the contact plate; and c. anelectrically conductive connector strip having a first portion overlyingand attached to a portion of the insulating sheet and insulated from thecontact plate thereby, the connector strip having a second portionsubstantially perpendicular to the first portion of the strip and havingan end away from the first portion.
 6. A multicell battery as defined inclaim 5 in which the electrically conductive contact plate and theelectrically conductive connector strip are made of metal.